1. Field of the Invention
This invention relates generally to a tape cassette which is particularly suited to be made smaller in size than the standard compact tape cassette, and also is directed to a tape recorder for use with such relatively smaller tape cassette.
2. Description of the Prior Art
Heretofore, a tape cassette which is smaller in size than the standard compact tape cassette has been used to permit miniaturization of the corresponding cassette-type tape recorder. When such relatively smaller tape cassette is loaded or positioned in the tape recorder intended therefor, a run of the magnetic tape within the cassette body is grasped between a capstan and pinch roller of the tape recorder so as to be driven at a constant speed thereby in a recording or reproducing operation, and a magnetic head is introduced into the cassette body through a window at the front thereof for engagement with the magnetic tape run therebehind so as to record or reproduce signals thereon. By reason of such engagement of the magnetic head with the tape run, the latter is brought into frictional contact with a guide pole which is integral with the cassette body inside the latter at a position in advance of the magnetic head, considered in the direction of the movement of the tape run. By thus bringing the tape into frictional contact with the guide pole, the running magnetic tape is provided with a suitable back tension and the tape run engaged by the magnetic head is stabilized and maintained in a substantially fixed position in respect to the head.
Since the guide pole for stabilizing the tape run is formed integrally with the cassette body molded of a synthetic resin, if the cassette body is deformed or distorted, the guide pole may also be distorted so that it is difficult to ensure precise uniformity of the configuration and position of the guide pole in various interchangeable tape cassettes. Particularly, it is difficult to maintain true circularity of the guide pole and its precise perpendicularity relative to the upper and lower walls of the cassette body. As a result, with the prior art tape cassette, it is difficult to ensure stability of the tape run engaged by the magnetic head during recording and reproducing, whereby satisfactory recording and reproducing characteristics may not be attained.